Triggers Of Atrial Fibrillation Research Articles

Appropriate Selection of Substrate Ablation for Persistent Atrial Fibrillation Using Intraprocedural Assessment.

It has not been fully elucidated which patients with persistent atrial fibrillation (PerAF) should undergo substrate ablation plus pulmonary vein isolation (PVI). This study aimed to identify PerAF patients who required substrate ablation using intraprocedural assessment of the baseline rhythm and the origin of atrial fibrillation (AF) triggers.Methods and Results: This was a post hoc subanalysis using extended data of the EARNEST-PVI trial, a prospective multicenter randomized trial comparing PVI-alone and PVI-plus (i.e., PVI with added catheter ablation) arms. We divided 492 patients into 4 groups according to baseline rhythm and the location of AF triggers before PVI: Group A (n=22), sinus rhythm with pulmonary vein (PV)-specific AF triggers (defined as reproducible AF initiation from PVs only); Group B (n=211), AF with PV-specific AF triggers; Group C (n=94), sinus rhythm with no PV-specific AF trigger; Group D (n=165), AF with no PV-specific AF trigger. Among the 4 groups, only in Group D (AF at baseline and no PV-specific AF triggers) was arrhythmia-free survival significantly lower in the PVI-alone than PVI-plus arm (P=0.032; hazard ratio 1.68; 95% confidence interval 1.04-2.70). Patients with sinus rhythm or PV-specific AF triggers did not receive any benefit from substrate ablation, whereas patients with AF and no PV-specific AF trigger benefited from substrate ablation.

The circadian pattern of atrial fibrillation onset

Abstract Background/Introduction Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia affecting 2% of the population. Within the broad spectrum of AF symptomatology, there is a particular subset of patients that show a predominant or even exclusive nocturnal onset of paroxysmal AF. Purpose The aim of this study is to assess the timing of onset of AF in the 24-hour cycle and to assess whether a circadian rhythm is present in the onset of AF. Methods The MEDLINE, EMBASE, and CENTRAL databases, searched from inception to September 2023, provided 18 studies detailing the onset of AF in a 24-hour cycle. Patients had either paroxysmal or persistent AF. Studies performed in ICU populations (n=3) were omitted due to different triggers for AF. Time of AF onset was determined either by Cardiac Implantable Electronic Device (CIED) (n=5), Holter (n=7) or minute history taking (n=3). The presence and statistical significance of a 24-hour periodicity is tested using the cosinor analysis: Y(t)= A ⋅ sin(2πft + α) + β where the amplitude, frequency, phase and error (A, f, α and β, respectively) are computed by single harmonic regression using a nonlinear least-squares method. Goodness of fit is estimated using R2, the statistical significance of the model is tested using a zero-amplitude test. Results The 15 studies included 2.080 patients with 11.886 onsets of AF. The blue bars in Figure 1 represent the total of AF onsets from all studies per hour. The pattern of onset AF can be approximated well by a single sine function (Onset(t)= 95.7915 ⋅ sin((2π ⋅ 0.0417 ⋅ t) – 1.8386) + 510.5500, R2 0.77, P = 0.03) with a 24-hour period, clearly establishing the 24-hour rhythmicity in the onset of AF (Figure 1, red line). Hours with significantly more onset of AF compared to the mean, assessed by residual Chi2 testing, are exclusively nocturnal (22.00-7.00, indicated by a moon symbol in Figure 1) while hours with significantly less onset are exclusively during daytime (7.00-22.00, indicated by a sun symbol in Figure 1). Conclusion Despite the potential limitations due to the methods used, such as arrhythmia discrimination in CIED-studies and asymptomatic episodes in case of history taking, the overall picture of predominance of nocturnal AF onset is clearly established. Multiple pathophysiological mechanisms might underlie this circadian pattern and nocturnal predominance, like obstructive sleep apnea and increased vagal tone, which should be subject of further research.time of onset of AF over a 24h period

Impact of Atrial Fibrillation Triggers on Long-Term Outcomes of a Second Catheter Ablation of Nonparoxysmal Atrial Fibrillation.

Background: Catheter ablation (CA) of atrial fibrillation (AF) triggers, including non-pulmonary vein (PV) foci, contributes to improved procedural outcomes. However, the clinical significance of an AF trigger ablation during second CA procedures for nonparoxysmal AF is unknown. Methods and Results: We enrolled 94 patients with nonparoxysmal AF undergoing a second CA. Intracardiac cardioversion during AF using high-dose isoproterenol was performed to determine the presence or absence of AF triggers. PV re-isolations were performed if PV potentials recurred, and if AF triggers appeared from any non-PV sites, additional ablation was added to those sites. We investigated the incidence of atrial arrhythmia recurrence (AAR) >3 months post-CA. Of the 94 enrolled patients, AF triggers were identified in 65 (69.1%), and of those with AF triggers, successful elimination of the triggers was achieved in 47 patients (72.3%). Multivariate analysis revealed that no observed AF triggers were a significant predictor of AAR (hazard ratio [HR] 1.97, 95% confidence interval [CI] 1.21-3.46, P=0.019). In a subanalysis of the patients with AF triggers, multivariate analysis showed that unsuccessful trigger ablation was significantly associated with AAR (HR 5.84, 95% CI 2.79-12.22, P<0.01). Conclusions: Having no observed AF triggers during a second CA session significantly increased the risk of AAR, as did unsuccessful CA of AF triggers.

The Role of Immune Cells Driving Electropathology and Atrial Fibrillation.

Atrial fibrillation (AF) is the most common progressive cardiac arrhythmia worldwide and entails serious complications including stroke and heart failure. Despite decades of clinical research, the current treatment of AF is suboptimal. This is due to a lack of knowledge on the mechanistic root causes of AF. Prevailing theories indicate a key role for molecular and structural changes in driving electrical conduction abnormalities in the atria and as such triggering AF. Emerging evidence indicates the role of the altered atrial and systemic immune landscape in driving this so-called electropathology. Immune cells and immune markers play a central role in immune remodeling by exhibiting dual facets. While the activation and recruitment of immune cells contribute to maintaining atrial stability, the excessive activation and pronounced expression of immune markers can foster AF. This review delineates shifts in cardiac composition and the distribution of immune cells in the context of cardiac health and disease, especially AF. A comprehensive exploration of the functions of diverse immune cell types in AF and other cardiac diseases is essential to unravel the intricacies of immune remodeling. Usltimately, we delve into clinical evidence showcasing immune modifications in both the atrial and systemic domains among AF patients, aiming to elucidate immune markers for therapy and diagnostics.

Exploring synthesis as a vital cognitive skill in complex clinical diagnosis.

Clinicians employ two main cognitive approaches for diagnoses, depending on their expertise. Novices typically use linear hypothetico-deductive methods, while experts rely more on intuitive pattern recognition. These closely correspond to System 1 and System 2 thinking described in behavioral economics. We propose that complex cases additionally require the cognitive skill of synthesis, to visualize and understand the connections between various elements. To illustrate the concept, we describe a 60-year-old individual with a 6 h history of chest pain, fever, cough, accompanying chronic heart failure, atrial fibrillation, COPD, thyrotoxicosis, and ischemic heart disease. Facedwith such a scenario, a bedside approach adapted by clinicians is to generate a list of individual diagnoses or pathways of pathogenesis, and address them individually. For example, this cluster could include: smoking causing COPD, IHD leading to chest pain and heart failure, and thyrotoxicosis causing atrial fibrillation (AF). However, other interconnections across pathways could be considered: smoking contributing to IHD; COPD exacerbating heart failure; IHD and pneumonia triggering atrial fibrillation; thyrotoxicosis and AF, independently worsening heart failure; COPD causing hypoxemia and worsening ventricular function. The second cluster of explanation offers a richer network of relationships and connections across disorders and pathways of pathogenesis. This cognitive process of creatively identifying these relationships is synthesis, described in Bloom's taxonomy of the cognitive domain. It is a crucial skill required for visualizing a comprehensive and holistic view of a patient. The concept of synthesis as a cognitive skill in clinical reasoning warrants further exploration.

A novel designed atrial septum linear ablation method (Icho line) for non-pulmonary vein triggers originating from atrial postero-septum and crista terminalis

Abstract Background Therapeutic strategy for non-pulmonary vein (PV) trigger of atrial fibrillation (AF) has not been well established although they are the major cause of AF recurrence after PV isolation. The atrial postero-septum or right atrial crista terminalis (CT) are the common non-PV trigger sites of AF. For them, a focal ablation is often insufficient due to a regional arrhythmogenicity. We devised an original linear ablation method, named "Icho Line". Icho means ginkgo in Japanese. Methods Eight hundred and thirty-two AF ablation patients were retrospectively studied. An AF induction test was conducted after each PV isolation procedure. Non-PV triggers from the postero-septum or CT that initiate AF were analyzed. Premature atrial contractions that did not initiate AF were excluded. A linear ablation was designed horizontally from the anterior right PV isolation line to fossa ovalis in the left atrium. In the right atrium, the opposite side of the left atrial ablation and CT were continuously ablated like the shape of a ginkgo leaf (Figure 1). Results A hundred and fifteen non-PV triggers were detected in 104 patients (12.5%), among which Icho line ablation was performed in 39 patients (37.5%) with documented triggers from the postero-septum or CT (Figure 1). Atrial tachyarrhythmia recurrence free rate in the Icho line group and other non-PV ablation patients were 61.8% and 45.4%, respectively (P=0.54, Figure 2). Conclusions A novel designed Icho line is a feasible and effective ablation strategy covering non-PV triggers from the atrial septum and CT.Icho Line Figure 1Icho Line Figure 2

Pesticide exposure an unforseen trigger for atrial fibrillation

Abstract Background/Introduction Over the last few decades, the use of pesticides for improving crop yield has continued to soar. Recent evidence shows the residuals of pesticides in many fruits and vegetables in the local supermarket. Although acute exposure to pesticides has been related to various severe illness, including cardiovascular dysfunction, chronic pesticide exposure has been poorly studied. Herein we study the cardiotoxic effect of commonly used pesticides to the most common cardiac arrhythmia, atrial fibrillation (AF). Purpose Whether exposure to commonly-used pesticides triggers AF if so, explore the underlying molecular mechanism. Methods Ten commonly used pesticides in the Netherlands, including glyphosate, MCPA and boscalid, were used to study cardiotoxicity using experimental Drosophila and rat model systems for AF. Drosophila were exposed to three varying pesticide concentrations, ranging from reported environment concentrations, LD50 and high dose, followed by survival and heart wall measurements (heart rate (HR) and arrhythmicity index). In addition, rats were exposed to four pesticides, paraquat, glyphosate, round-up and MCPA for 16 months followed by AF detection (ECG) and Westernblot and metabolomic analyses of the atrial tissue samples. Results A dose dependant survival curve was observed of Drosophila fed with pesticides compared to controls. In prepupae a significant reduction in HR and increase in arrhythmicity index was found for all? utilized pesticides. Furthermore, a significant increase in AF and atrial arrhythmic episodes was observed in rats treated with pesticides (15-70%) compared to non-treated control rats (0%). Metabolomic analyses in rats revealed a significant increase in mitochondrial supercomplexes and 6-phosphoglyconlactate levels in pesticide treated rats compared to controls, suggesting a role for mitochondrial and energy dysfunction to underlie pesticide-induced AF. Conclusion(s) This study provides evidence that chronic exposure to commonly-used pesticides in the Netherlands affects longevity, heart wall function in Drosophila and triggers atrial arrhythmia and AF in rats. Likely, the pesticides impair mitochondrial function and energy metabolism.

The air we breathe in - the impact of air pollution on hospitalized morbidity due to atrial fibrillation (EP-PARTICLES study)

Abstract Background Atrial fibrillation (AF) is the most common arrhythmia and environmental conditions are one of its risk factors. While the etiology of AF is multifactorial and includes other cardiovascular diseases like heart failure, some studies suggest that air pollution may play an important role in its development and progression. So far, they focus on the short-term influence of pollutants and mainly on particulate matters (PMs). Moreover, the type of pollution that occurs in Poland, called "Polish smog" - due to its composition and the conditions in which it is formed - is characterized by extremely adverse health effects. Purpose Analysis of the impact of air pollution on triggering atrial fibrillation episodes. Methods The study area included voivodeships of Eastern Poland. Data on hospitalizations for 2011-2020 were obtained from regional departments of the National Health Fund resulting in 882,277 hospitalizations. Non-emergency hospitalizations were excluded from further analysis. In the statistical analysis, the time-stratified panel data using Poisson regression techniques has been estimated. Day of the week, temperature, atmospheric pressure, and humidity with cubic spline transformation (df=3) were used as confounders. For long-term trends, a simple indicator variable technique was used. The association between PMs and the occurrence of AF is presented as odds ratios (OR) with 95% confidence intervals (CI). ORs for each pollutant at days with lag from 0 to 6, 0-6, and 0-30 were calculated separately. Results During the analysed period, a total of 311,645 hospitalizations for AF were recorded, including 252,566 emergency ones. The main pollutant affecting the occurrence of AF episodes was benzo(a)pyrene (BaP) – a 1 mg/m3 increase in BaP concentrations (lag0-OR=1.078, 95%CI 1.054-1.102; P&amp;lt;0.001) resulted in an increase in emergency hospitalizations for AF. Hospitalized morbidity due to atrial fibrillation was also influenced by PM2.5 (lag0-OR=1.035, 95%CI 1.031-1.039; P&amp;lt;0.001), SO2 (lag0-OR=1.015, 95%CI 1.007-1.023; P&amp;lt;0.001), and NO2 (lag0-OR=1.022, 95%CI 1.016-1.027; P&amp;lt;0.001). This effect persisted for 7 days [lag0-6 (BaP-OR=1.121, 95%CI 1.09-1.153; P&amp;lt;0.001), (PM2.5-OR=1.047, 95%CI 1.042-1.052; P&amp;lt;0.001), (SO2-OR=1.032, 95%CI 1.022-1.043; P&amp;lt;0.001), (NO2-OR=1.032, 95%CI 1.024-1.041; P&amp;lt;0.001)]. Conclusions Variations in air pollution levels, especially BaP and PM2.5, can increase the risk of acute AF incidents. We associate these pronounced adverse health effects with the particularly toxic effects of Polish smog. There is a need for further research that will focus on the mid– and long–term effects of pollution on AF which will help to elucidate the underlying pathomechanisms and develop effective strategies for prevention. Reducing air pollution levels may have significant public health benefits in terms of lowering the burden of AF and other cardiovascular diseases.Graphical abstract

Abstract 12216: A Novel Designed Atrial Postero-Septum Linear Ablation Method (Icho Line) for Non-Pulmonary Vein Triggers of Atrial Fibrillation (AF)

Introduction: Therapeutic strategy for non-pulmonary vein (PV) triggers of atrial fibrillation (AF) has not been well established although they are the major cause of AF recurrence after PV isolation. The atrial postero-septum or right atrial crista terminalis (CT) are the common non-pulmonary vein (PV) trigger sites of atrial fibrillation (AF). For them, a focal ablation is often insufficient due to a regional arrhythmogenicity. We devised an original linear ablation method, named "Icho Line” covering the non-PV triggers from this area. Methods: Eight hundred and thirty-two AF ablation patients were retrospectively studied. An AF induction test was conducted after each PV isolation procedure. Non-PV triggers were detected in 104 patients (12.7%), among which Icho line ablation was performed in 39 patients (37.5%) with documented triggers of AF from postero-septum or CT. A linear ablation was designed horizontally from the anterior right PV isolation line to fossa ovalis in the left atrium. In the right atrium, the opposite side of the left atrial ablation was continuously ablated toward the CT like the shape of a ginkgo leaf (Figure). Results: Atrial tachyarrhythmia recurrence free rate in the Icho line group and other non-PV ablation patients were 61.8% and 45.4%, respectively (P=0.54, Figure). Recurrence with atrial tachycardia was very rare in the Icho line group. Conclusions: A novel designed Icho line is a feasible and effective ablation strategy covering non-PV triggers from the atrial septum and CT.

Abstract 17749: Regionalization of Non-Pulmonary Vein Triggers for Atrial Fibrillation When the P Wave is Obscured Using Non-Invasive Electrocardiographic Imaging QRS-T Subtraction Algorithm

Introduction: Ablation of non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation (PVI) may reduce atrial fibrillation (AF) recurrence. Localizing a trigger which initiates AF after a single atrial ectopic beat is challenging, especially in the scenario when the trigger P wave is obscured by preceding QRS-T complex. Aim: To evaluate the potential for noninvasive electrocardiographic imaging (ECGi) to localize NPVTs when the P wave morphology is superimposed on the T wave of the previous beat. Methods: We developed an algorithm which overlays and subtracts the preceding QRS-T wave complex from the QRS-T wave complex which is obscuring the P wave of interest, thus revealing the P wave morphology (Figure 1A). Resultant unobscured P waves (from multiple body surface electrodes) are then used for ECGi computation. In five patients undergoing AF ablation, after PVI, we paced from 15 atrial sites where NPVTs commonly arise, and evaluated the epicardial activation maps generated by ECGi both when pacing was timed to ensure an unobscured P wave and when timed to coincide with preceding QRS-T complex. Co-registration of CT-based ECGi activation maps with invasive electroanatomic map (EAM) allowed comparison of the earliest activation site on ECGi map from both the obscured P waves after QRS-T subtraction and unobscured P waves with true pacing locations on EAM (Figure 1B). Results: From 146 pacing sites in our patient cohort, for the unobscured P waves, median distance between earliest site on ECGi map and EAM pacing location was 16 mm (10-21 mm), and for obscured P waves after QRS-T subtraction, median distance was also 16 mm (12-23 mm) (Figure 1C). Conclusion: Using a QRS-T subtraction algorithm, ECGi can approximate origin of paced P waves whether P wave is unobscured or obscured by the preceding QRS-T complex. Spontaneous NPVT P waves are commonly obscured by the QRS-T wave and the ability to rapidly localize an early coupled P wave may facilitate NPVT mapping and ablation.

Predictors of pulmonary vein non-reconnection in the second procedure after ablation index-guided pulmonary vein isolation for atrial fibrillation and its impact on the outcome.

Although first-pass isolation (FPI) of the pulmonary vein (PV) has been suggested as a marker for PV isolation (PVI) durability, it has not been confirmed. Non-PV atrial fibrillation (AF) triggers were the main target in patients without PV reconnection in the second ablation procedure, but the outcome was unclear. We aimed to validate FPI as a marker of PVI durability and evaluate the outcome after the second procedure in patients without PV reconnection by comparing it to those with reconnection. Among the 2087 patients undergoing the first ablation index-guided radiofrequency AF ablation, 309 with atrial tachyarrhythmias (ATs) recurrence and undergoing the second procedure were studied. Clinical characteristics and outcomes were compared between the patients without PV reconnection (PV non-reconnection group, n = 142) and with reconnection (PV reconnection group, n = 167). FPI in both PV sides in the first ablation procedure was significantly more frequent in thePV non-reconnection group (77.5%) than in thePV reconnection group (45.5%) (p < .001). Multivariate logistic regression analysis revealed that FPI (odds ratio, 3.71 [95% confidence interval, 2.23-6.19], p < .001) was the only predictor of PV non-reconnection. Radiofrequency applications for non-PV AF triggers were more frequently performed in thePV non-reconnection group (40.8% vs. 24.6%, respectively, p < .001). Kaplan-Meier analysis revealed that AT recurrence-free rate was significantly lower in thePV non-reconnection group (1-year recurrence-free rate, 62.7% vs. 75.4%, respectively; p = .01 by log-rank test). FPI was the only independent predictor of PV non-reconnection. Despite aggressive ablation for non-PV triggers, AT recurrence was more frequent in patients with PV non-reconnection.

Utility of short-time electrocardiogram to assess risk for atrial arrhythmia recurrence: Impact of atrial premature beat occurrence 1 day after pulmonary vein isolation for atrial fibrillation.

Atrial premature beats (APBs) are the trigger for atrial fibrillation (AF). We sought to investigate the clinical significance of APB occurrence 1 day after pulmonary vein isolation (PVI) for AF using a short-time electrocardiogram. A total of 206 patients undergoing PVI for paroxysmal AF were included. Electrocardiogram recording for 100 consecutive beats was performed 1 day after PVI. The patients were divided into two groups: those with reproducible APBs (≥1 beat) during reassessment (APB group, n = 49) or those without (non-APB group, n = 157). Late recurrence was defined as atrial tachyarrhythmia recurrence 3-12 months after PVI. The impact of APB occurrence on outcomes was investigated. Late recurrence occurred in 19 patients (9.2%). The presence of low-voltage areas, left atrial volume, and recurrence rate were higher in the APB group than in the non-APB group. In the APB group, the patients with recurrence had lower prematurity index (PI, coupling interval of APB/previous cycle length) compared to those without. Receiver-operating characteristic analysis revealed PI (<59.3) to be a predictive factor of recurrence (area under the curve: 0.733). The study subjects were then reclassified into three groups according to the absence of APB occurrence (n = 157), presence thereof with PI ≥ 59.3 (n = 33), and presence with PI < 59.3 (n = 16). The multivariate Cox models revealed that APB with PI < 59.3 was an independent predictor for recurrence (hazard ratio, 8.735; p < 0.001). A short-time electrocardiogram enables risk assessment for arrhythmia recurrence, and APB with low PI 1 day after PVI is a powerful predictor.

Focal activity in atrial fibrillation: state of the art

Focal activity is one of the dominant triggers of atrial fibrillation. Its activity is revealed in paroxysmal as well as in persistent patterns of arrhythmia. Starting as a trigger of atrial fibrillation in pulmonary veins, over time with increasing of burden of atrial fibrillation, focal activity is more and more revealed out of pulmonary veins: anterior and posterior left atrial walls, interatrial septum, coronary sinus, ligament of Marshal and right atrium. Diagnostics of focal activity is a challenging clinical task despite implementation of mathematical algorithms of electrogram analysis because of its spatial instability and activation direction of the mapping electrode. All these items are discussed in the article.

Additional left atrial lesions improve the effect of cryoballoon pulmonary vein isolation in paroxysmal atrial fibrillation patients

Aim. Cryoballoon ablation (CBA) is one of the methods for catheter pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF). Left atrial additional lesion (LAAL) to PVI were proposed to eliminate extrapulmonary AF triggers. Nonetheless whether the additional lesions improve CBA effectiveness is not clear.Methods. Primary CBA procedures performed for paroxysmal AF during 2017-2021 were analyzed. The study group (Algorithm group, n=82) was recruited prospectively in 2019-2021. As the first step CBA PVI were performed in all pts. In those who were on sinus rhythm (SR) after the PVI, AF induction attempts with burst atrial pacing were performed. Pts with induced AF and those who stayed on AF after PVI underwent LAAL at the left ganglionated plexus area. In case of stable SR (non-inducible AF) the procedure finished. If AF was inducible or did not terminate during CBA, the second LAAL set were performed - LA posterior wall lesions. If AF was still inducible or did not terminate, the SR was restored by electrical cardioversion. The control group (Control group, n=94) was formed retrospectively from patients with routinely performed only CBA PVI with achievement of isolation criteria in 2017-2019. If AF continued, sinus rhythm was restored by cardioversion. There were no attempts of induction AF during the procedure.Results. The Algorithm and Control groups were comparable in terms of clinical, demographic and electrophysiological characteristics. At 12 months postoperatively, the effectiveness was higher in the Algorithm group than in the Control group (78.0% vs. 62.8%, p = 0.044). No adverse effects were found.Conclusion. Thus, the stepwise approach with LAAL increases the effectiveness of CBA in the long-term period and does not affect the risk of complications.

RENIN-ANGIOTENSIN-ALDOSTERONE BLOCKADE AND ITS PREDICTION OF LATE RECURENCE OF ATRIAL FIBRILLATION AFTER RADIOFREQUENCY ABLATION

Objective: Hypertension is one of the main triggers of atrial fibrillation. Patients with hypertension have 1.7 times higher risk of developing atrial fibrillation. Opinions differ on the use of RAAS blockers in atrial fibrillation. The aim is to evaluate the effect of RAAS blockers in the prevention of atrial fibrillation on the post-ablation prognosis of the patient. Design and method: A retrospective analysis of 221 patients who underwent radiofrequency ablation of atrial fibrillation at the First Department of Internal Medicine - Cardioangiology of St. Anne's University Hospital in Brno from 1 January to 31 December 2019 was performed. Recurrence within the first three months was designated as early, and in the following months as late. Results: The median age of the study population (N = 221) was 63 years, with 67.4% of men. According to pre-ablation transesophageal echocardiography, the mean left atrial dimension was 45.3mm and left ventricular ejection fraction was 59.8%. Among the comorbidities, hypertension (63.3%) and dyslipidaemia (41.6%) were the most common, followed by diabetes mellitus (14.0%), ischemic heart disease (7.2%), history of stroke (6.3%), chronic obstructive pulmonary disease (5.0%). 33.0% had a history of nicotinism. Among the baseline antihypertensive groups, beta-blockers were the most represented (69.2%) followed by angiotensin-converting enzyme inhibitors (37.5), angiotensin-receptor blockers (20.4%), calcium channel blockers (32.1%) and diuretics (32.1%). There was not a significant difference in the representation of each group of antihypertensives between the populations. n the group of patients treated with ACEis/ARBs (57.9%), the mean blood pressure resulting from pre- and post-ablation measurements was the same 149/81mm Hg. No significant differences in left atrial size or capture of early or late postablation recurrence (HR 1.26, 95% CI 0.84-1.90, p = 0.265) were detected in the RAAS inhibitor group relative to patients without ACEis/ARBs in therapy. Conclusions: Conventionally administered ACEis/ARBs before ablation procedure did not lead to a reduction in the detection of late postablation recurrence of atrial fibrillation. Despite the documented benefit of RAAS blocker therapy in atrial fibrillation patients, their routine administration before ablation procedure aimed at improving postablation prognosis was not evaluated as justified.

Arrhythmic substrate in pulmonary vein isolation reprocedures in the era of the close protocol

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The CLOSE protocol was developed as a radiofrequency ablation strategy that would result in the safe creation of durable pulmonary vein isolation (PVI) leading to improved outcomes. The aim of the protocol is to enclose the PVs with stable, contiguous and ablation index (AI) guided lesions. Purpose We analyze the arrhythmic substrate found in patients undergoing PVI reprocedure after a first CLOSE-PVI procedure and compare it to that observed in PVI reprocedure in patients who underwent a first non-CLOSE-PVI procedure. Methods Patients undergoing a PVI-reprocedure after a first CLOSE-PVI procedure (35W, AI 450 for the anterior wall and 350 for posterior wall) were prospectively included (CLOSE-group). During the reprocedure a detailed electroanatomical map with multielectrode catheters was obtained in all patients. The number of reconnected PVs and segments was assessed. In patients with left atrial flutter (AFl), the circuit was defined by activation and entrainment mapping. These data were compared to those observed in a historic control group of PVI reprocedures after a first non-CLOSE-PVI procedure (non-CLOSE-group; 21 reprocedures among 157 first PVI procedures). Results Among 352 patients undergoing a first CLOSE-PVI, 27 (74.1% male, 57±8.6 years) underwent a PVI reprocedure. 74% (20 patients) showed at least 1 PV reconnected vs 100% in non-CLOSE group; p=0.012. Among the 7 patients without PV reconnection (PVR) perimitral AFl was found in 2 patients and a roof dependent AFl was observed in 1 patient. In the remaining 4 patients no specific substrate or trigger was observed. Among patients showing PVR, no differences were observed in terms of mean number of reconnected PVs [2(1-2) vs 2(1-3) respectively; p=0.751] or segments [2(1-2) vs 2(2-4) respectively; p=0.895) compared to the non-CLOSE group. Conclusion PVR remains the main substrate in patients undergoing atrial fibrillation (AF) ablation reprocedure after a first CLOSE-PVI. However, a significantly higher proportion of patients showed persistent PVI without a specific arrhythmic substrate or trigger for AF; which makes it necessary to define new strategies to improve rhythm control in these patients.

Impact of effective refractory period personalization on prediction of atrial fibrillation vulnerability

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska- Curie grant agreement Introduction Although the effective refractory period (ERP) is one of the main electrophysiological properties governing atrial tachycardia (AT) maintenance, ERP personalization is rarely performed when creating patient-specific computer models of the atria to inform clinical decision making. State-of-the-art models usually do not consider physiological ERP gradients but assume a homogeneous ERP distribution. This assumption might have an influence on the ability to induce reentries in the model. Aim To evaluate the impact of incorporating clinical ERP measurements when creating in silico personalized models to predict vulnerability to atrial fibrillation (AF). Methods Clinical ERP measurements were obtained from three patients from multiple locations in the atria. The protocol for ERP identification consisted of trains of 7 S1 stimuli with a basic cycle length of 500ms followed by an S2 stimulus with a coupling interval between 300 and 200ms in decrements of 10ms until loss of capture. The atrial geometries from the electroanatomical mapping system were used to generate personalized atrial models. To reproduce patient-specific ERP, the established Courtemanche cellular model was gradually reparameterized from control conditions to a setup representing AF-induced remodeling. Three different approaches were studied: 1) a control scenario with no ERP personalization 2) a discrete split where each region had a single ERP value and 3) a continuous ERP distribution by interpolation of measured ERP data (Fig. 1). Arrhythmia vulnerability was assessed by virtual S1S2 pacing from different locations separated by 3cm. The number and location of inducing points and type of arrhythmia were determined for the three approaches. The mean conduction velocity was set to 0.7 m/s and the electrical propagation in the atria was modeled by the monodomain equation and solved with openCARP. Results Incorporating patient-specific ERP as a continuous distribution did not induce any reentrant activity. A summary of induced ATs is shown in Table 1. For patient A, AF was induced from 3 different locations with the control setup, whereas 9 ATs were induced with the regional method, of which 4 were AF and 5 macro reentries. For patient B, AF was induced from 1 point with the control setup; whereas with the regional approach, AF was induced at 4 points. For patient C, only one macro reentry was induced with the regional method. Conclusion Incorporation of patient-specific ERP values has an impact on the assessment of AF vulnerability. Furthermore, the type of personalization affects the likelihood of AF inducibility. The incorporation of more detailed ERP distributions may lead to a more accurate prediction of AF trigger points and could in the future inform patient-specific therapy planning. Larger cohorts need to follow to demonstrate the role of incorporating clinical patient-specific ERP values into personalized models for predicting AF vulnerability.

P59 SPONTANEOUS RESTORATION OF STABLE SINUS RHYTHM FOLLOWING EDGE–TO–EDGE TRANSCATHETER MITRAL REPAIR PROCEDURE WITH MITRACLIP IN A PATIENT WITH CHRONIC ATRIAL FIBRILLATION

Abstract Patients with history of atrial fibrillation (AF) undergoing mitral edge–to–edge repair procedure with Mitraclip tend to be relatively older, have more advanced valve disease, and suffer from more comorbidities than patients without AF [1;2]. Moreover, their all–cause mortality rate one year after the procedure and hospitalization rate for heart failure is higher than that of patients in sinus rhythm [3]. Therefore, managing patients with AF poses a greater challenge, and their prognosis is considerably worse. Improvement of mitral regurgitation following mitral edge–to–edge repair procedure with Mitraclip may reduce atrial volume overload positively impacting AF triggers. In this report, we present a case of spontaneous restoration of stable sinus rhythm in a patient with chronic AF undergoing mitral valve repair procedure with Mitraclip. The patient, 80 years old, underwent implantation of a clip on centro–lateral site of the mitral valve plane (A2–P2) with mild residual insufficiency and an optimal procedural result. The restoration of sinus rhythm, which occurred during the first hours after the procedure, proved to be stable at the 30th day control post–discharge. the indexed left atrial volume remained unchanged (LAVI 43–45 mL/m2). Literature on the frequency of spontaneous sinus rhythm restoration following edge–to–edge mitral repair with Mitraclip in patients with chronic AF is limited. In a sub–analysis of the COAPT study [4], in addition to the known benefits of the Mitraclip procedure, it was possible to highlight a significant reduction in the rate of stroke in patients with AF. This outcome could be attributed to the reduction of the AF burden associated with mitral valve insufficiency. More studies are although necessary to determine the procedure‘s impact in this specific clinical situation. Rreferences: [1] Velu JF, Am J Cardiol. 2017 Dec 1;120(11):2035–2040. [2] Saad AM, Catheter Cardiovasc Interv. 2021 May 1;97(6):1252–1256. [3] Shah S, Heart Fail Rev. 2021 May;26(3):531–543. [4] Gertz ZM, Circ Cardiovasc Interv. 2021 Apr;14(4):e010300.

PO-02-032 IMPACT OF ATRIAL FIBRILLATION TRIGGERS ON LONG-TERM OUTCOMES OF A SECOND CATHETER ABLATION OF NON-PAROXYSMAL ATRIAL FIBRILLATION

Catheter ablation (CA) for atrial fibrillation (AF) triggers including non-pulmonary vein (PV) foci contribute to improvement of CA outcome. However, we often experience AF recurrences after an AF trigger ablation in patients with non-paroxysmal AF (PaAF). A second CA session is performed in some cases after a failed first CA, but clinical significance of AF triggers ablation during second procedure in non-PaAF patients is still unknown. We retrospectively analyzed non-PaAF patients receiving a second CA session for eliminating AF triggers and clarified the clinical significance of an AF trigger ablation for the outcomes of the second CA session. 94 patients with non-paroxysmal AF [mean age 63.7 (56.0-72.0) years, 72.2% male] undergoing second CA were enrolled. Intracardiac cardioversion during AF using a high-dose isoproterenol was performed at the beginning of the procedure to determine the presence or absence of AF triggers. We performed re-PV isolation if PV potential recurred, and if AF triggers were appeared from any non-PV sites, we added an additional ablation to that site. In patients without AF triggers, linear ablation, such as left atrium (LA) roof line and/or LA bottom line, superior vena cava isolation, or both were added. Multivariate analyses were carried out to estimate clinical factors associated with late recurrence of AF (LRAF) which means AF recurrence later than 3 months after CA. Of the enrolled 94 patients, AF triggers were identified in 59 patients (70.2%). Of those with AF triggers, 42 patients (71.2%) archived successful elimination of AF triggers, but we could not eliminate all AF triggers in 17 patients (28.8%). During a mean follow-up period of 32.2 (range, 6.25-48.8) months, a total of 55 patients (58.5%) experienced LRAF. Among the patients with AF triggers, 33 (50.8%) experienced LRAF. On the other hand, among those without AF triggers, 22 (75.9%) developed LRAF. Multivariate analysis revealed that the absence of AF triggers was a significant predictor of LRAF [hazard ratio (HR); 2.02, confidence interval (CI); 1.13-3.62, p=0.018]. In sub-analysis in patients with AF triggers, multivariate analysis showed that an unsuccessful elimination of AF triggers was significantly associated with LRAF (HR; 5.06, CI; 2.40-10.68, p<0.001). The absence of AF triggers during the second CA session significantly increased the risk of an LRAF. When AF triggers were present, an unsuccessful AF trigger ablation resulted in poor outcomes.

PO-04-081 ISOLATION OF PERSISTENT LEFT SIDED SUPERIOR VENA CAVA USING PULSED FIELD ABLATION

Pulmonary vein foci account for more than 90% of triggers for atrial fibrillation, most commonly treated with complete pulmonary vein isolation. Non–pulmonary vein triggers are the drivers of atrial fibrillation in a subgroup of patients. One such trigger is a persistent left superior vena cava (SVC), which may contain remnant muscular and pacemaker tissue carried over from embryonic life. However, reported complications of radiofrequency ablation of this structure are significant, including vein stenosis, tamponade and phrenic nerve injury. Pulsed field ablation is a promising new technology that may be uniquely suited to avoid such a complications. This case illustrates the first known application of pulsed field ablation of a left sided SVC. N/A The patient is a fifty-two year old male with a history of coronary artery disease and persistent atrial fibrillation refractory to medical therapy including rate and rhythm control strategies. He is status post multiple cardioversions with restoration to normal sinus rhythm for a relatively short period of time. The patient underwent an ablation procedure at which time it was discovered that he had an isolated persistent left sided SVC. Pulmonary vein isolation was performed using a combined radiofrequency and pulsed field ablation lattice tip catheter (Affera inc., Watertown, MA). Accordingly to study protocol, lesions were placed using radiofrequency anteriorly and pulsed field lesions posteriorly in the left atrium around the pulmonary veins resulting in complete isolation. The patient also developed a counterclockwise typical atrial flutter which was ablated. Given the propensity for triggers from the SVC, pulsed field ablation was performed by creating a circumferential lesion set superiorly beyond the left superior pulmonary vein region and inferiorly near the mid coronary sinus below the left inferior pulmonary vein. A linear lesion set connecting these two regions was also performed along the atrial portion of the coronary sinus, with subsequent confirmation of exit block and elimination of all local electrograms. In patients with persistent left SVC, pulsed field ablation is feasible without the risk of phrenic nerve injury or tamponade from excessive contact force. Further studies are necessary to examine whether the complications associated with LSVC isolation can be minimized.